Environmental variables affecting an arid coastal nebkha.

Foredunes in arid coastal dune systems comprise nebkhas, which originate by interactions between vegetation and aeolian sedimentation. While continuous foredunes in temperate climates have been widely studied, knowledge of interactions between biotic and abiotic drivers in foredunes formed by nebkha is still scarce. With the aim of exploring variables affecting arid foredunes, a range of morphological, sedimentological, and vegetation characteristics were measured on a single nebkha formed by a Traganum moquinii plant located in the foredune of Caleta de Famara beach (Lanzarote, Canary Islands).

Nebkha development and sediment supply.

This study examines the role of sediment supply in controlling the formation and the spatial patterns of nebkha, numbers and sizes, present in foredunes fronting coastal dunefields of the arid northwest African and the Canary Islands coasts. Sediment supply is estimated qualitatively and quantitatively by various measures, and the number and size of nebkhas are obtained on a range of beach-dune systems. In the case of the Canary Islands, LiDAR data and orthophotos with high spatial resolution (0.

Different tolerance to salinity of two populations of Oenothera drummondii with contrasted biogeographical origin.

Oenothera drummondii is a native species from the coastal dunes of the Gulf of Mexico that has nowadays extended to coastal areas in temperate zones all over the world, its invasion becoming a significant problem locally. The species grows on back beach and incipient dunes, where it can suffer flooding by seawater, and sea spray. We were interested in knowing how salinity affects this species and if invasive populations present morphological or functional traits that would provide greater tolerance to salinity than native ones.